Abstract P169: Randomized Controlled Trial Comparing a Self-guided vs. Dietitian-led Approach Using Web-based Tools to Lower Blood Pressure: Study Design and Rationale

Background: Weight loss, consumption of a Dietary Approaches to Stop Hypertension (DASH) dietary pattern, reduced sodium intake, and increased physical activity have been shown to lower systolic blood pressure (SBP). Use of website or smartphone-based tools could be potentially scalable solutions to improve lifestyle behaviors and lower SBP, but little data exists to support their use in clinical practice. Methods: In an ongoing single-center, 2-arm, randomized controlled trial, we compare the efficacy of a dietitian-guided approach vs. a self-guided approach in lowering 24-hour SBP in overweight/obese patients with 24-hour SBP 120-160 mmHg on 0-1 BP medication. As part of standard of care, participants with outpatient SBP ≥ 130 mmHg are identified using Geisinger electronic health record data and through Geisinger Health Plan’s health and wellness program and invited to complete 24-hour ambulatory BP monitoring (ABPM). Qualifying participants are then invited to a research visit to sign informed consent and for data collection, including a web-based food frequency questionnaire (Viocare®), which provides personalized recommendations to improve dietary quality. After a 2-week run-in period in which participants must regularly log data into www.bmiq.com, a comprehensive weight management program, and a smartphone app (Lose It!), participants are randomized 1:1 to a self-guided arm or a dietitian-led arm. All participants are instructed to use the website and app, and the dietitian-led arm additionally receives weekly telephone calls from registered dietitian nutritionists, trained in motivational interviewing. The primary outcome is 3-month change in 24-hour SBP. Other outcomes include changes in other ABPM measures, total healthy eating index-2015 (HEI) score, weight, waist circumference, metabolic equivalent of task-minutes per week (International Physical Activity Questionnaire short form), and study satisfaction. Results: Out of 210 patients who have thus far completed ABPM, 128 were eligible for the trial, 85 consented for the trial, and 78 were randomized after completing the run-in period. In a preplanned interim analysis of the first 34 randomized patients, 28 (82%) completed the 3-month study visit. Mean (SD) changes from baseline to 3 months were: -8.0 mmHg (9.9) for 24-hour SBP, -5.4 kg (4.5) for weight, -6.1 cm (7.4) for waist circumference, and 11.2 units (12.0) for HEI score. Conclusions: Confirmation of elevated BP using ABPM may provide an opportunity to engage patients in making lifestyle modifications, as more than 60% of eligible patients after 24-hour ABPM screening were successfully randomized into the trial. Completion of the study is expected by the end of 2020 and will determine the efficacy of a self-directed vs. dietitian-led approach to lower 24-hour SBP using web-based tools.